Retractable devices, objects of the invention, are found mostly in the field of lipsticks, so the description of the advantages of the invention in relation to the state of the art shall be given for lipsticks, with the understanding that this application is solely indicative and not limiting.
Retractable devices must allow a product to be taken out of a protective device in order to be used, then retracted after use in order to return to a storage position wherein they are protected. As the product is used in the extended position, the device must be able to support an axial force that authorises the application of the product, without the latter retracting spontaneously, such an effect is called anti-push back.
In addition, the user of the product must feel a certain comfort during the extracting and retracting of the product and the product must optionally be easy to adjust—this is in particular the case with lipsticks for which the user be easily be able to adjust the level of extension of the product allowing for precise and comfortable application, and this as the cake of makeup product is progressively used.
U.S. Pat. No. 6,244,770 B1 discloses a lipstick container comprising a case comprising a spiral, a sheath and a cup comprising a pin, the pin being displaced in a longitudinal sheath window and the pin comprising a flat spot increasing the coefficient of friction between the spiral and the pin in the direction of retraction. The increase in the coefficient of friction allows the product to resist a more substantial push back force before being retracted. However, the force provided by the user to manoeuvre the device is also stronger which decreases the comfort of use for the user.
European Patent No. EP 0461001 B1 discloses a lipstick container comprising a case comprising a spiral, a sheath and a cup comprising a pin, the pin being displaced in a longitudinal sheath window and the pin comprising a shoulder allowing for a blocking of the pin at the beginning and at the end of the stroke.
Such a device allows the product to resist a large force in the totally extended and totally retracted positions, however a small rotation of the cup in relation to the sheath unlocks the cup and the product is retracted therefore entirely without great resistance to the push back, yet the application of the product typically takes place in a position that is partially extended from the device, even though this position has a mediocre resistance to the push back.
European patent application No. EP 0799589 A1 discloses a lipstick container comprising a case comprising a spiral, a sheath and a cup comprising a pin, the pin being displaced in a longitudinal sheath window and the pin comprising a particular form in such a way as to increase the coefficient of friction between the spiral and the pin in the direction of retraction of the product. The device disclosed in said patent application makes it possible to increase the force beyond which the product is retracted. However, the force is also more substantial when the user wants to retract the product.
All of the aforementioned documents disclose means for modulating the coefficient of friction between the cup, the sheath and the spiral. However, in all of these devices the coefficient of friction is determined by design and is uniform for a given device all throughout the stroke of the cup. None of the aforementioned documents of prior art disclose a container that makes it possible to modulate the displacement speed or the coefficient of friction of the cup according to the position of the cup in the sheath.